In order to obtain clues for elucidating pathogenetic mechanism of cerebellar neurodegenerative disorders, we established murine cerebellar neuronal hybridomas by somatic cell fusion with a neuroblastoma cell line. Several neuronal hybridoma cell lines growing well in vitro and expressing GABA could be identified by immunostaining with anti-GABA antibody. However, we could not detect markers known to be specific for cerebellar Purkinje cells. After culturing these cells under serum-free condition, a part of them also expressed immunoreactivity against tyrosine hydroxylase. This indicates that neuronal properties expressed in these neuronal hybridomas are not always derived from those expressed in parental cerebellar neurons, and that neuronal properties of these hybridomas can change under culture conditions. Since we now realize that neuronal hybridomas are inadequate for studying the expression of neuronal properties, we gave up producing cerebellar neuronal hybridomas from murine models of human cerebellar degenerations, such as pcd, and comparing those with neuronal hybridomas established from normal littermates. Instead, we have made cDNA libraries from these mutant and normal cerebella, and are now trying to identify genes, the expression of which is deferent between them, using differential hybridization method.